Neurosurgical procedures, such as procedures operating on the brain, may involve the placement of cortical stimulator electrodes against the outer surface of the brain to monitor electrical activity or apply electrical pulses to the brain. The cortical stimulators are generally placed against the outer surface of the brain, at locations selected manually, based on the surgeon's recognition of gross anatomical features of the brain surface (e.g. the locations of sulci and gyri). As a result, it may be unclear which electrical activity is being measured or stimulated by the cortical stimulators.